You might want to look at the arrow type class and the instance for (->). Ben On 28 May 2013 09:56, "Dominique Devriese" < dominique.devriese@cs.kuleuven.be> wrote:
Hi all,
I often find myself needing the following definitions:
mapPair :: (a -> b) -> (c -> d) -> (a,c) -> (b,d) mapPair f g (x,y) = (f x, g y)
mapFst :: (a -> b) -> (a,c) -> (b,c) mapFst f = mapPair f id
mapSnd :: (b -> c) -> (a,b) -> (a,c) mapSnd = mapPair id
But they seem missing from the prelude and Hoogle or Hayoo only turn up versions of them in packages like scion or fgl. Has anyone else felt the need for these functions? Am I missing some generalisation of them perhaps?
Regards, Dominique
_______________________________________________ Haskell-Cafe mailing list Haskell-Cafe@haskell.org http://www.haskell.org/mailman/listinfo/haskell-cafe